A violet compound of manganese (A) decomposes on heating to liberate oxygen and compounds (B) and (C ) of manganese are formed. Compound (C ) reacts with KOH in the presence of potassium nitrate to give compound (B). On heating compound (C ) with conc. `H_(2)SO_(4)` and NaCl, chlorine gas is liberate and a compound (D) of manganese alongwith other products is formed. Identify compounds A to D and also explain the reaction involved.

Explanation

`A=KMnO_(4) , B=K_(2)MnO_(4), C = MnO_(2), D = MnCl_(2)`
Reaction `: underset((A))(2KMnO_(4))overset(Delta)(rarr)underset((B))(K_(2)MnO_(4))+underset((C ))(MnO_(2))+O_(2)`
`2MnO_(2)+4KOH +O_(2)rarr2K_(2)MnO_(4)+2H_(2)O`
`MnO_(2)+ 4NaCl+ 4H_(2)SO_(4) rarr underset((D))(MnCl_(2))+2NaHSO_(4)+2H_(2)O+ Cl_(2)`